Last month’s column (February 2015) addressed the potential situation where the design engineers specify a change to a system which has already passed its commissioning functional performance test. Although inconvenient and somewhat costly so late in the project, that situation is handled through normal project change processes, retesting, and updated documentation.
This month, however, I am going to address another potential testing phase challenge. This time the commissioning professional discovers, during functional performance testing, that the systems are programmed and controlled differently than originally designed and different from the approved control system submittals. There are two flavors of this situation.
The as-installed and as-programmed systems meet all of the Owner’s Project Requirements (OPR), just in a different way than specified by the design engineers. In this case, the commissioning professional should document the as-installed and as-programmed systems for the design engineers’ review and approval. If the design engineers do not approve the modified systems, the situation will be treated as any other deficiency found during functional performance testing.
Or, the as-installed and as-programmed systems may be “close enough” to meeting the OPR criteria that the owner will agree to accept them as is. In this case, the commissioning professional should document the as-installed and as-programmed systems and describe in detail how they deviate from achieving the original OPR criteria. This should be reviewed by both the design engineers and the owner for approval. If the systems are not acceptable to both the owner and the design engineers, the modification will be treated as any other deficiency found during functional performance testing.
If the design team and owner approve any system changes unilaterally made by the installation and/or controls contractors that are subsequently discovered through commissioning testing, it is critical that these be documented for the record and for reference by future O&M staff. The following additional steps are required to maintain the integrity of the commissioning process and its value to the owner:
1. Revise the systems manual to reflect accepted system changes. This may include OPR documentation, sequences of operation, schematic diagrams, systems integration descriptions, and recommissioning test procedures.
2. Conduct a supplemental training session (assuming O&M training had previously been delivered) to explain system modifications and any related operational strategy changed.
This was just another example of how late-in-the-project surprises can cost everyone on the project time (money) and can stress the project closeout schedule. Avoiding this type of situation is a big part of why we have design and construction phase commissioning activities. Early confirmation of design understanding, system configurations, required control sequences, set points, alarms, on-board equipment controller integration, etc., is critical to keeping everyone on the same page regarding system performance expectations at the end of construction.